Resinous reaction product of urea and formaldehyde



' benefits of this invention are primarily ap- Patented May 29, 1928.

UNITED STATES PATENT OFFICE.

FELIX LAUTER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR I COMPANY, A CORPORATION OF 'DELAWARE.

' RESINOUS REACTION PRODUCT No'Drawing. Application filed May 7,

It has been known for many years that resin-like substances can be produced by causing a reaction to take place between urea and formaldehyde, and there have always the type described which are free from this impurity. Methylene urea is of a crystalline nature instead of being resinous, and will not act like a resinous body, even under the influence of heat and pressurea. The

parent in connection with the production of transparent bodies, but even if non-transparent resinous bodies are to be made, as for example in making moulding mixtures, the presence of methylene urea is disadvantao'eous, as it tends to weaken the strength of the product. p

I have found that the production of mc'thvlene urea can be avoided if the ureawhlle hot, to a boil ng is added gradually, formaldehyde solution. If the two substances are mixed in a cold state and allowed or UREA AND FORMALDEHYDE.

1926. Serial No. 107,491.

to stand, the methylene urea will form at the end of several hours, but if the two are mixed cold and then heated to bring on the condensation reaction, the methylene urea is formed immediately. 7 It is essential to pre vent the formation of this impurity that the .is applicable to the recognized equivalents of urea and formaldehyde.

What-I claim-isz 1. The process of forming resinous reaction products of urea and formaldehyde which are free from methylene urea, which TO ROI-1M & HAAS comprises the step of adding hot urea to a boiling" solution of formaldehyde.

2. A process as defined in claim 1, in which the urea is added in the form of a hot solution.

3. A process as defined in claim 1, in which the urea is in the form of a hot solution and is added gradually to the boiling solution of formaldehyde.

' FELIX LAUTERM 

